The opportunistic human pathogen Candida albicans and other non-albicans species have acquired considerable clinical significance as infectious agents in immunocompromised patients, being important causes of morbidity and mortality. The recommended therapy relies on fluconazole, voriconazole and caspofungin. In fact, also many of the new possible antifungal agents that can be found in the literature possess an azole core.
The pathogenic species of Candida derive their relevance not only from the severity of the infections but also from their ability to develop resistance against a variety of antifungal agents. In fact, widespread and prolonged use of azoles has led to the rapid development of multidrug resistance, which poses a major hurdle in antifungal therapy. Many of the currently available drugs have become ineffective against new or re-emerging fungi because of the rapid development of resistance. These problems have give rise to the need to develop new effective antifungal agents. Accordingly, in the last years, new structural classes of antifungal agents were reported, among which guanidine derivatives proved to have very interesting inhibitory activity. As an example, guazatine (a mixture of guanidines and polyamines used in agriculture as fungicide) was classified as a moderately hazardous antifungal agent, while results from in vivo animal studies demonstrated a high potential for guazatine and related compounds as antifungal agents. Authors have recently reported that components of guazatine are able to act toward albicans and non-albicans Candida species.